Speaker system for fijeie alarms



y 1939- G. J. SCHWALL ET AL 2,156,356

SPEAKER SYSTEM FOR FIRE ALARMS Filed March 18, 1957 AMPLIFIER INVENTOR GJSC/M/d/ J. EM Car/y BY Q 9.5m

ATTORNEY Patented May 2, 1939 QM AT 5.5

PATENT F 2,156,356 s EAa n Y M, R El ie 14 155 il egn ry J. Schwall and James E. McCarty,

only by theoperator on duty in theeentral station and a-message as to the location, character of. the fire, etci, had to be ascertained by said operator from the person on the telephone ;and then transmitted: by the operator to the engine "houses; Considerable time was sometimes thus unavoidably consumed before the necessary engine company started for the scene 20 of'thefire.

. It is with the telephone method of giving alarms that'our-invention deals, and our principal 'object is to provide a system by means of which',"'when "a "person telephones in an alarm, such telephonic conversation is transmitted, to and heard'in amplified tones simultaneously in all the engine'hou'ses'aswell as in the central station wher'thernessage is initially received. In this manner; details and information as to the 0 firegivenb'ythe'personputtingin the alarm, in response; if necessary,-to"queriesbythecentral station bperatonare immediately heard by those on duty in the various engine houses and the firemen 'can' instarmyieavfifor the" scene, with information of value'fonthe prompt'fighting' of '3, the"firewhen'theyarrive'r 1 Another object of our invention is to provide a system for the purpose which" makes use of the circuit :already provided in" connection with alarm 40 circuits;withoutinterfering in'a'ny way with the operation"of"'the'latter;" In this manner, but

' little additional 'wi'ririg'f'andno' extra cables are neededirr addingbur equipment to'a system alreadyinstall'ed andthecost ofthe'additional installatiorris"'thus'kept'"down to 'a'minimumj E3, Asiisual'in"connectiomwith the telephoning in of an 'alarmto' "the-central station, the tape register and other equipment whichmake some distracting noises are "automatically actuated.

r n conne t on .wi h t pe ation r. sy tem i9,- ths iq c t s a so. enp i pt. ur, inv nti to temporarily discontinue the operation of the register, etc., and consequently "stop any distracting noises made thereby, while a' telephone a a m s be n e 're n t ansmi e "t the if? were en e i i'e' here j h 'r q nothing to prevent the central station operator receiving the call from'properly catching all that isfsaid over the telephonejand likewise'those hearing the message in the enginehouses will not have theirjatter tion distracted from the mes- 6 sage being" given them.

A furtherobject ofthe invention is to produce a simple and inexpensive device and yet one which will be; exceedingly effective for the purpose'for which'it is designed.

These objects we accomplish by means or such structure and relative arrangement of parts as will fully appear by a perusal 'of the following, specification and claims.

"Ifhe figure on the drawing is a diagram ofa fire alarm system, showing only those features o f a standard alarm circuit necessary to our invention. V

"Referring now more particularly to the characters 0f reierence on the drawing, the main alarm circuit, which is always closed as required by the fire underwriters, leads into the central station C and thence to the various engine houses H, the alarm sounding devices in the various engine houses beingall in series in the 25 circuit. Said' circuit comprises an incoming wire I leading into the station C and having electrically actuated alarm and recording devices such as a gong G and a-register R interposed in series inthe circuit. Said wire beyond the de- 0 vices leads to one terminal of anormally closed relay switch S which includes a movable blade 2. From thisblade another wire 3 extends thence to an engine house H'where a loud-speaker 4, as well as another register R andgong G are 351 interposed'inseries therein. A condenser 5 of suitable capacity is interposed in an auxiliary wire 3a which is connected to the wire 3 at points ahead of and beyond the register and gong as shown, and-thus by-passes the same. 4Q From said engine house the circuit continues to and through the other engine houses, being initially inthe form of a wire 6 connected to the wire 3. Interposed in the circuit in each of these other engine houses is a loud speaker, a gong and 4Q a register, disposed in series in the circuit in the same arrangement as above described and as shown on the drawing. From the last engine house in the system a wire 1 leads back to the central station C, where 'it connects with one 5 terminal of another normally closed relay switch S, which' 'includesa movable blade 8 to which saidwire I is connected. Another wire 9 connected to the other terminal'of said switch and having a'source of power l0 interposed therein a. I V V. (a

leads from the central station and forms the other incoming wire of the alarm circuit.

When an alarm is given by the opening of the main alarm circuit in the usual manner, the

various gongs and registers in all the engine houses as well as in the central station are actuated, and though the loud speakers are in the circuit, they do not interfere with the functioning of the alarm system. The latter thus functions in the normal manner.

The incoming telephone lines H, by means of which fires are verbally reported to the central station operator, are of course connected to a receiving telephone T in said station. Wires I2 with a manual control switch l3 and condensers M therein are connected to the wires H and lead to an amplifier unit A of a standard type, there being a transformer Na, in the line ahead of the amplifier. This amplifier unit is located in the central station, power for which unit is provided by means of wires l connected to any suitable source of 110 v. A. C. current. It should here be noted that the capacity of the amplifying unit is sufiicient to take care of as many loud speakers as may be necessary for any particular installation, and, if required, a number of these units can of course be used to give the desired result.

Also connected to the amplifier unit is a microphone M located adjacent the telephone T so as to be convenient to the operator answering the telephone. The switch 13 is also located convenient to said operator. A loud speaker l6, connected to the amplifier, is mounted in a convenient position in the central station, a hand switchlfia being interposed in the speaker line. It will thus be seen that when a telephone alarm is received and answered by the operator he may causethe message, as received, to be amplified and broadcast generally into the central station, by closing the switches l3 and Ilia.

At the same time he may, if it appears necessary, cause the conversation to be simultaneously broadcast from the speakers 4 in the various engine houses by means of the following circuit arrangement. Connected to the amplifier unit is an auto transformer I! one wire l8 from which leads to a normally open terminal of the switch S. The other wire 19 from the transformer ll leads to a normally open terminal of the switch S. When the relays of these switches are actuated, the blades 2 and 8 respectively are moved to break the circuits to the wires l and 9 and close the same to the wires l8 and I9. The circuit wires 3 and i of the engine house circuit and in which the engine house loud speakers 4 are interposed as previously described, are thus connected in circuit with the amplifier unit. Sound waves passing through the circuit from the telephone wires are thus amplified and broadcast into the engine houses, as well as in the central station, so that the listeners in the engine houses will instantly hear the telephonic alarm as it is being given and can act accordingly. Also, if necessary, in connection with this operation of the loud speaker system, the central station operator may talk into the microphone and thus transmit instructions or other information to the men in the various engine houses.

The current then flowing through the line and actuating the loud speakers is much weaker than that used and necessary in actuating the gongs and registers, and if the latter were left in the circuit at that time, they would absorb so much of this relatively weak current that the speakers would be rendered practically inaudible. For this reason the various auxiliary by-pass condensers 5 are employed. The condensers 5 are necessary however since when the main normal or alarm circuit is closed, the necessary current must then fiow through the gong and register coils to hold the same.

Actuation of the various relay switches (which are arranged in a compact unit and are of a standard character which'may be purchased on the open market) is preferably accompanied with the aid of a spring opened foot switch 20 interposed in the relay circuit wires 2!, said switch being convenient to the foot of the operator seated at the desk upon which the telephone T is disposed. In this manner both hands of the operator are free for manipulating the telephone, writing down notes or other uses.

In order that the volume of sound emitted from the central station speaker I6 shall 'be modulated according to the load in the speaker circuit, the inductance 22 of the speaker mechanism is of an adjustable character, its adjustment being controlled by a relay 23 interposed in the circuit 2| of the other switch relays. Said inductance 22 is set so that when only the speaker is is operating, the resistance is relatively great so that the volume of sound emitted from the speaker IE will not be unduly loud. When the load on the line is increased by the closing of the circuit to the engine house speakers, the resistance of the speaker I6 is automatically lessened so that the relatively small amount of current still available for the operation of said speaker is sufficient to produce the desired volume of sound.

As previously explained, the operation of the register and gongs in the engine houses will be automatically discontinued when the loud speakers are broadcasting, so that they will not give forth any noises to distract the attention of the listeners from the verbal alarms being broadcast. It may here be noted that when the alarm circuit is opened by the closing of the speaker circuit, the gongs and registers in the engine houses will be momentarily actuated. If no speech then comes from any speaker (as it should instantly) the crew in the corresponding engine house will know that their speaker is not functioning for some reason, and can report the fact to the central station.

The operation of the register and gong in the central station however are not normally affected by the closing of the speaker circuit, and in order to temporarily cut them out to eliminate the noise we provide the following arrangement:

A wire 2% is connected tothe line 9 beyond the source of current l0 and leads to one terminal of a normally open relay switch 25, to the other terminal of which the wire I is connected. The wire 24 has a resistance 26 therein equal to that of the outside lines. The relay 2'! of the switch 25 is connected to the circuit 2| of the other switch relays so as to be actuated therewith upon the closing of the foot switch 20. When the relay switch 25 is closed therefore a short circuit between the wires I and 9 is established, in which the resistance is so great that the adjacent gong G and register R will not be actuated.

In connection with the operation of the amplifier, through the tubes of which current is always flowing .to keep them warm, it is not desirable that the 13 current shall fio-w through these tubes amcew;

unless the speaker circui tself: iSw IQSQd; B circuit is therefore normally broken wiresv 28'. of said circuit lead:: to; a n rrnally;- o-pen is disposed-to close-theB circuit. From theforegoing description ,itwill beread- 11y seen that we have producedesuchagdev qe-as substantially,fulfillsthe; objects of the invention as set forth: herein.

While this specification sets forth in detail the present and preferred construction of the device, still in practice such deviations from such detail may be resorted to as do not form a departure from the spirit of the invention, as defined by the appended claims.

Having thus described our invention, what we claim as new and useful and desire to secure by Letters Patent is:

1. In a fire fighting system which includes a central station and an engine house separate from said station, and an alarm circuit leading into the central station and thence to the engine house, alarm producing mechanism interposed in the circuit within the engine house, a loud speaker interposed in the circuit within the engine house, a sound amplifying unit in the central station, a telephone line from the outside con-- nected to the amplifier, circuit wires leading from the amplifier, and means operable selectively from within the central station to connect said wires to the alarm circuit wires lea-ding to the engine house.

2. A system as in claim 1, with a loud speaker disposed in the central station and directly connected to the amplifier.

3. In a fire fighting system which includes a central station, an engine house separate from said station, an alarm circuit leading into the central station and thence to the engine house and an audible alarm in said circuit within the engine house; a normally closed switch in the circuit in the central station, a loud speaker interposed in the circuit within the engine house, a sound amplifying unit in the central station, a telephone line from the outside connected to the amplifier, circuit wires leading from the amplifier, and means to simultaneously open said switch and connect the wires to the alarm circuit between the switch and engine house.

4. A system as in claim 3, with means functioning automatically to prevent actuation of the audible alarm when said wires are connected to the alarm circuit.

5. A system as in claim 3 with a wire connected to the alarm circuit across the alarm therein, and a condenser in said wire.

6. In a fire fighting system which includes a central station, an engine house separate from said station, an alarm circuit leading into the central station and thence to the engine house and an audible alarm in said circuit within the engine house and another such alarm in the circuit within the central station; a loud speaker interposed in the circuit within the engine house,

a sound amplifying unit in the central station, a

telephone line from the outside connected to the amplifier, circuit wires leading from the amplifier, a selectively operated switch to connect the said wires to the alarm circuit, and means to simultaneously prevent the central station alarm from functioning. 1

7. A verbal fire alarm system for use in connection with a plurality of separated engine o e and a ent l atio mmitment al rma circuit; extending frornthe central station til-3 1 1::

e tne nehq se t a arm produc n ha s nterncs dz n he. c r uit. vni hinthee e ner muse.

loud speakers; interposed in the circuit within all.- ethcu esl; aqun am l fy n un in h tral station, a telephoneline from the outside e arate: om thetalarm c cuit and. co nected to thean plifie-r, and-means operable at;will fromwithinthe central station to- ,selectively, connect heam ifie healarm circuit; r

8. In a fire alarm system which includes a central station, an engine house separate from said station and a two-wire alarm circuit leading into the central station and thence to the engine house, each wire having a gap therein and a movable switch blade across the gap and connected to the wire on the engine house side of the gap and normally re'leasably engaging the wire on the other side of the gap to close the circuit, a loud speaker in the circuit within the engine house, a telephone line from the outside, a sound amplifying unit connected to the line, a pair of circuit wires leading from the amplifier and terminating adjacent and normally spaced from the switch blades to be engaged thereby when said blades move away from the alarm circuit wires, and selectively operable means to thus move the blades.

9. In combination with a fire alarm system, including an alarm circuit leading to an engine house, an alarm producing mechanism interposed in the alarm circuit within the engine house; a separate telephone circuit, and a loud speaker interposed in the alarm circuit within the engine house, the alarm circuit and telephone circuit being arranged in operative connection.

10. In combination with a fire alarm system, including an alarm circuit leading to' an engine house, an alarm producing mechanism interposed in the alarm circuit within the engine house; a separate telephone circuit, a loud speaker interposed in the alarm circuit within the engine house, and switch means to selectively connect the telephone circuit with the alarm circuit.

11. A combination as in claim 10, including means to disconnect the alarm circuit, said switch means being arranged-to connect the telephone circuit with that side of the alarm circuit when disconnected which includes the loud speaker within the engine house.

12. In combination with a fire alarm system, including an alarm circuit leading to an engine house, and alarm producing mechanism interposed in the alarm circuit within the engine house; a loud speaker interposed in the alarm circuit within the engine, a separate telephone circuit, a sound amplifying unit connected with said telephone circuit, and means to selectively connect said sound amplifying unit with the alarm circuit.

13. A system as in claim 12, in which said amplifying unit is disposed in a central station; there being a loud speaker in said station and directly connected to said amplifying unit.

14. A system as in claim 12, in which said amplifying unit is disposed in a central station; there being a microphone in said central station directly connected to said amplifying unit.

15. In combination with a fire alarm system, including an engine house, a central station, and an alarm circuit extending between the engine house and central station, said alarm circuit including alarm producing mechanism interposed therein and disposed within the engine house; a 7

separate telephone circuit leading to the central station from the outside, a loud speaker interposed in the alarm circuit within the engine house, and switch means in the central station arranged to selectively connect the telephone circuit with the alarm circuit.

16. A combination as in claim 15, including means in the central station to disconnect the alarm circuit; said switch means being arranged to connect the telephone circuit at a point on the engine house side of said alarm circuit when so disconnected.

17. A system as in claim 1, with a loud speaker disposed in the central station and directly connected with the amplifier; and including means to automatically modulate the volume of sound from the central station loud speaker when said amplifier circuit wires are connected with the alarm circuit wires.

GREGORY J. SCHWALL. JAMES E. McCAR'I'Y.- 

